Needs for picking up images of patients who are difficult to move from hospital rooms, urgently picking up images in an operating room, etc. have recently increased in medical fields, and a mobile X-ray apparatus which is movable to a hospital room or the like to perform X-ray imaging has been broadly popular. Recently, a mobile X-ray apparatus having an image reading device for reading image information from IP is being put into practical use so that a picked up X-ray image is immediately checked at an image pickup place to determine at that place whether re-imaging is required or not.
For example, Patent Document 1 discloses an X-ray apparatus for doctor's round visits which is equipped with an image information reading device for reading image information accumulated in IP. According to this X-ray apparatus for doctor's round visits, image information read out by the image information reading device is transmitted to a CRT display fixed on a top surface of a main body to display an X-ray image.
The image reading device scans a laser beam in a main scan direction (a direction perpendicular to an auxiliary scan direction) while feeding IP in the auxiliary scan direction to successively scan the whole IP surface and detect photostimulable emission light at each point, thereby reading image information. In order to obtain an accurate image, it is important to perform the feeding of IP and the laser scanning accurately with high precision, and it is not preferable that vibration, impact or inclination is applied when image information is read.    Patent Document 1: JP-A-4-190224